1. Field of the Invention
The present invention relates to a single-lens reflex camera system n which an image pickup lens can be changed, and particularly relates to a setting and a control of a diaphragm value during photographing.
2. Description of Related Art
Among the conventional single-lens reflex camera systems, there was a system in which a photographing diaphragm value is set in an operator that is mounted on a single-lens reflex camera body (hereinafter, called a body unit), and also there was a system in which the photographing diaphragm value is set in an operator mounted on a lens unit that is changeable with respect to the body unit.
In the system in which various kinds of operations are performed in an operator that is mounted on the body unit, the setting of the diaphragm value in a diaphragm driving mechanism that is mounted on the lens unit is performed in the operator in the body, and thus the photographer may be confused until he/she becomes accustomed to the operations. Whereas, in the system in which the diaphragm value is set in the operator that is mounted on the lens unit, the diaphragm driving mechanism and the operator are mounted on the lens unit, and thus the photographer is not likely to be confused as mentioned above.
Moreover, conventionally, considering the compatibility with the system in which the diaphragm value can be set in the lens unit, some systems in which the diaphragm value also can be set in the operator in the body unit exist. However, in such systems, since the diaphragm driving mechanism and a diaphragm value setting portion in the lens unit are linked mechanically, there are problems in that the setting may be limited (for example, the diaphragm value setting portion must be provided at a certain position in the lens unit), or the operation may be complicated.
JP 7(1995)-311405 A discloses a technique that improves the operation of the diaphragm setting by providing the diaphragm value setting portion in the lens unit.
However, in the configuration disclosed in JP 7(1995)-311405 A, there is a problem in that, when the lens unit that does not include the diaphragm value setting portion is attached to the body, the diaphragm value cannot be set. For example, there is a problem of incapability of photographing in a diaphragm priority mode.